Device for alignment of cylindrical workpieces for magnetic-discharge welding

ABSTRACT

A device for alignment of cylindrical workpieces for magnetic-discharge welding is provided with external and internal aligning sleeves (2,3) installed in an induction heater (1) coaxially and overlapping each other; the external aligning sleeve (2) is made of a non-polarizable dielectric material and features a ledge (4) on the outer surface thereof so that it can be locked by one of the aligning disks (5); the internal aligning sleeve (3) is made of a non-magnetic material having low conductivity and provided, on the inner surface thereof, with step-like shaped through slots (7) and, on the outer surface thereof, with a ledge (6) limiting the depth to which the sleeve (3) can be introduced into the external aligning sleeve (2); the internal aligning sleeve (3) is locked in relation to the induction heater (1) by means of a second aligning disk (10) contiguous to the ledge (6).

TECHNICAL FIELD

This invention relates to metal processing and welding by intensemagnetic fields and, in particular, to a device for alignment ofcylindrical workpieces for magnetic-discharge welding of metals.

BACKGROUND ART

The problem of metal processing and welding stabilization aimed atreducing rejects and saving metal has become extremely important. Thequality of workpiece processing and welding largely depends on theaccurate and durable adjustment of technological equipment andmachine-tool attachments used in the production process.

Such requirements are particularly stringent in case ofmagnetic-discharge welding where only one discharge of the capacitorbank is required for welding and repeated discharges are of no use andthe workpiece is rejected. Many researchers and product engineers areengaged in trying to solve the problem of alignment of workpiecesaffecting the quality of metal processing and welding.

Known in the art is a device for alignment of cylindrical workpieces (A.E. Slukhotsky, "Induktory", 1965, p. 24) which comprises aligning disksmade of asbestos cement and installed on the butt face ends of theinduction heater.

These disks are provided with openings through which pipes are suppliedto the hardening zone.

But this device for alignment of workpieces is deficient in that thedepth to which the pipe is introduced into the induction heater zonecannot be regulated. In addition, the asbestos cement soils the outersurface of workpieces to be welded together in the process of themagnetic-discharge welding.

Besides, this device for alignment of pipes cannot provide reliableinsulation of the workpieces from the work-coils of the inductionheater.

DISCLOSURE OF THE INVENTION

The invention is to provide a device for alignment of cylindricalworkpieces for magnetic-discharge welding, which can ensure accuratepositioning of workpieces in relation to one another and controlleddepth of introduction of workpieces into the zone of the inductionheater, while retaining the reliability, simplicity and durability ofthe device.

This is attained by that a device for alignment of cylindricalworkpieces for magnetic-discharge welding, comprising aligning disksinstalled on the butt surfaces of an induction heater, according to theinvention, is equipped with external and internal aligning sleevesinstalled in the induction heater coaxially and overlapping each other,the external aligning sleeve being made of a non-polarizable dielectricmaterial and provided with a protrusion on the outer surface thereof, towhich one of the aligning disks is contiguous to arrest this sleeve,while the internal aligning sleeve is made of a non-magnetic materialhaving low conductivity and provided, on the inner surface thereof, withstep-like shaped through slots and, on the outer surface thereof, with aprotrusion limiting the depth of introduction of the internal sleeveinto the external aligning sleeve and ensuring arrest of the internalsleeve in relation to the induction heater by means of a second aligningdisk contiguous to said protrusion.

The external and internal aligning sleeves provided in the inductionheater ensure external alignment of workpieces to be welded together inrelation to each other.

The external aligning sleeve is made of a non-polarizable dielectricmaterial in order to ensure reliable insulation of workpieces from thework-coil of the induction heater, while the protrusion or ledge on theexternal surface of the aligning sleeve permits this sleeve to be lockedin relation to the induction heater in order to achieve stable weldingconditions.

The internal aligning sleeve is made of a non-magnetic material havinglow conductivity in order to allow magnetic force lines free access tothe workpieces and thus reduce to the minimum any losses ofelectromagnetic power and, also, to keep workpieces in place. Thethrough shaped slots provided in the internal sleeve permit oxide filmsand gases to be removed from the welding zone.

The protrusion provided on the external surface of the internal sleevelimits the depth of introduction of said sleve into the externalaligning sleeve and its motions in relation to the induction heater.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWING

The invention will now be described in greater detail with reference tospecific embodiments and an accompanying drawing showing a general viewof a device for alignment of cylindrical workpieces formagnetic-discharge welding, according to the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

A device for alignment of cylindrical workpieces for magnetic-dischargewelding, according to the invention, comprises an induction heater 1accommodating an external aligning sleeve 2 and an internal aligningsleeve 3 arranged coaxially and overlapping each other.

The external aligning sleeve 2 is made of a non-polarizable dielectricmaterial, e.g. fluoroplastic, ensuring reliable insulation of workpiecesbeing welded (not shown in the drawing) from the work-coil of theinduction heater 1. A ledge 4 is provided on the outer surface of thesleeve 2 near the butt end of the induction heater 1. An aligning disk 5installed on the butt face of the induction heater 1 is contiguous withsaid ledge 4. The ledge 4 and the aligning disk 5 lock the externalsleeve 2 in the working zone of the induction heater 1, holding thesleeve 2 from longitudinal motions.

The internal aligning sleeve 3 is made of a non-magnetic material, e.g.titanium or stainless steel. A ledge 6 is provided on the outer surfaceof the sleeve 3 near the butt face of the induction heater 1 in order tolimit the depth to which the sleeve 3 can be introduced into theexternal sleeve 2 and into the work zone of the induction heater 1.

The sleeve 3 also features, on the inner surface thereof, step-likeshaped slots 7 which are to reduce the effect of eddy currents and serveas ducts for removal of oxide films and gases from the welding zone.

The slots 7 of a step 8 of the internal sleeve 3 are communicated with astep 9 of the sleeve 3, having a larger inner diameter.

The step 8 of the sleeve 3 is to transport and align the workpieces tobe welded, while the step 9 is to reduce the resistance to the flows ofgases and oxide films transported along the slots 7.

An aligning disk 10 is contiguous with the ledge 6 of the sleeve 3 sinceit is secured on the second butt face of the induction heater 1. Thisdisk 10 is to correct any mechanical bends or misalignments of thesleeve 3.

The device for alignment of pipes for magnetic-discharge weldingoperates as follows.

Workpieces are prepared for welding and placed into the device. Themovable workpiece is placed into the external sleeve 2 until it ispressed against the internal sleeve 3. The stationary workpiece isplaced into the step 8 of the internal aligning sleeve 3 so that itoverlaps the movable workpiece. The butt end of the sleeve 3 is the stopfor the movable workpiece being welded, which limits its introductioninto the welding zone. In this manner the two workpieces to be weldedare reliably and stably locked in the device for the welding period.

After the workpieces are placed in the device, the magnetic-dischargewelding is started. As welding progresses, gases and oxide films arefreely removed along the slots 7 provided in the internal aligningsleeve 3 with practically no effect on the walls of the externalaligning sleeve 2. In this manner welding process is made stable, andthe service life of the external aligning sleeve 2 and the internalaligning sleeve 3 is made much longer.

The device proposed herein for alignment of cylindrical workpieces formagnetic-discharge welding is reliable in operation, its design isuncomplicated, it ensures stable welding throughout the perimeter of thecylindrical workpieces being welded together.

INDUSTRIAL APPLICABILITY

This invention can be used for processing and welding of metalcylindrical workpieces by intense magnetic fields, which may be found inmanufacturing refrigeration plants, motor building and cryogenicindustries, and many other fields.

I claim:
 1. A device for alignment of pipes for magnetic-dischargewelding, comprising aligning disks installed on butt faces of aninduction heater, characterized in that the device is provided with anexternal aligning sleeve (2) and an internal aligning sleeve (3)installed in the induction heater (1) coaxially and overlapping eachother, the external aligning sleeve (2) being made of a non-polaraizabledielectric material and provided with a ledge (4) on the outer surfacethereof, to which one of the aligning disks (5) abuts to lock theexternal aligning sleeve (2), while the internal aligning sleeve (3) ismade of a non-magnetc material having low conductivity and provided, onthe inner surface thereof, with step-like shaped through slots (7) and,on the outer surface thereof, with another ledge (6) limiting the depthto which the internal aligning sleeve (3) can be introduced into theexternal aligning sleeve (2); the internal sleeve (3) is locked inrelation to the induction heater (1) by means of a second aligning disk(10) contiguous to the another ledge (6).